These papers are transmitted to me for advice on the legal questions raised in Mr Knowles's memorandum of 2 December 1920.

These questions are:

Whether the Commonwealth, under its power as to external affairs, can enter into a convention dealing with a matter (e.g. railway rates) which, under the existing distribution of powers by the Constitution, falls within the domain of the States.

Do the provisions of Article 5 of the draft Convention on Freedom of Transit adequately safeguard the Commonwealth in relation to the immigration of persons whose immigration, or the importation of goods whose importation, is not absolutely but only conditionally prohibited?

(1) Opinions have been given by Mr Attorney-General Isaacs(1) (5 May 1906) and by Mr Attorney-General Groom(2) (19 June 1908) that where the Commonwealth has adhered to a treaty, it has power under the category of external affairs', to pass all necessary legislation for securing the fulfilment of its treaty obligations.I agree with those opinions.

The mere fact that the subject-matter of the treaty is not one of the enumerated subject-matters of Commonwealth legislative power does not reserve the subject-matter exclusively to the States; legislative power in respect to matters falling within that subject-matter is exercisable by the Commonwealth so far as it falls within the subject-matter of external affairs, just as it is exercisable so far as it falls within the subject-matter of, e.g. taxation, or external or interstate trade or commerce.

I therefore am of opinion that this power of the Commonwealth to enter into or adhere to a treaty is not affected by the question whether the subject-matter of the treaty is one of the enumerated subject-matters of Commonwealth legislative power.

For the purpose of these particular Conventions, however, it is not necessary to establish such a wide proposition. The subject-matter of them all falls within the category of trade and commerce with other countries.

Although railway rates on State railways are ordinarily a matter of State jurisdiction the Commonwealth has always claimed power to control them so far as interstate commerce is concerned (e.g. see Inter-State Commission Act 1912, section 18), and it must clearly have the same power where commerce with other countries is concerned.

As regards the power of the Commonwealth executive to adhere to or enter into a treaty, I think it is coextensive with the legislative power as above defined and that the Commonwealth can therefore adhere to the Conventions under consideration.

(2) Article 5 of the Draft Convention on Freedom of Transit provides that:
None of the High Contracting Parties shall be bound by the present Convention to afford transit for passengers whose admission into its territories is proscribed, or for goods belonging to a class of which the importation is prohibited, either on grounds of public health or security, or with a view to the prevention of diseases of animals or plants.

I am of opinion that these words cover persons and goods whose admission is prohibited subject to conditions. That is to say, if the admission is prohibited unless certain conditions are fulfilled, then the Convention does not bind the Commonwealth to admit them for transit unless those conditions are fulfilled. I think, therefore, that the interests of the Commonwealth in this respect are sufficiently safeguarded.